Refrigerating apparatus



NOV. 24, 1936. F ZELLHQEFER 2,061,606

REFRIGERATING'APPARATUS Filed July 20, 1934 INVENTOR. GLEN/V F.ZELL//0FR BY M A TTORNE Y.

Patented I Nov. 24, 1936 UNITED STATES PATENT OFFICE 10 Claims.

This invention relates to improvements in refrigerating apparatus and more particularly to refrigerating apparatus of the absorption type when employed in connection with an air conditioning device.

It is an object of this invention to provide means for controlling the operation of an apparatus of this character to. prevent conditions arising which affect the efilcient operation of the rean absorption type of refrigerating apparatus in connection withan air conditioning device in which the heat for the operation of the refrigerating apparatus is provided by an electrically operated and controlled fluid fuel burner boiler and the air conditioning device provided with a motor driven fan blower for circulating air therethrough, and illustrating the wiring diagrams to the various operating parts and controls.

Figure 2 is a fragmentary view of Figure 1 i1- lustrating a. modified form.

A steam boiler 13 is shown provided with an electrically operated and controlled fluid fuel burner device F and-connected by a pipe I to a coil of pipe 2 within a heater or still H, forming a part of the absorption refrigerating apparatus, with the lowermost coil thereof connected by a pipe 3 to a pump 4 for returning the condensate to the boiler B, which pump is operated by an electric motor E.

The absorption refrigerating apparatus includes a rectifier R in communication with the upper side of the heater H and an absorber A communicating on the under side with a chamber V containing the float of the float-operated valve.-

The rectifier R is connected by a pipe 5 to the condenser -C which also acts as a receiver. The bottom of the condenser and receiver C is connected by a pipe 6 through an expansion valve 1 to the upper manifold 8 of a cooling coil or evaporat'or 9, the lower manifold ill of which is connected by apipe ,II to the absorber A.

A solution of the desired solvent and refrigerant is introduced into the heater H, in the manner hereinafter described. The heat from the steam coil 2 boils off the refrigerant which passes in gaseous form through the rectifier R and pipe 5 5 to the interior of the condenser C where its temperature is reduced and the refrigerant becomes a liquid which passes through the pipe 6 and expansion valve 1 to the coolingcoil or evaporator 9 and therein absorbs heat from the'surrounding l0 atmosphere in returning to its gaseous form, and the gaseous refrigerant is delivered through pipe I to the interior of the absorber A. The solvent from which the refrigerant has been boiled off in the heater H collects in the bottom thereof and 15 passes through the pipe l2 and through the inner smaller pipe l3 of the heat exchanger X and then through pipe M to the inner smaller coil l5 of the residual heat coil Y, and from there through pipe [6 to be discharged in the form of a spray at the top of the absorber A so that. the gaseous refrigerant returning from the cooling coil or evaporator 9 goes into solution with the solvent and passes into the chamber V from which the solution is circulated through pipe ll, pump I8 driven by the motor M, and pipe l9 communicat ing with the larger outer coil 20 of the heat exchanger X and from the top of the coil 20 through the pipe 2| to be discharged in the form of a spray in the heater H above the coil 2. I

The float 22 in the chamber V controls a throttling valve 23 in the pipe I6, so that as the level of the solution in the chamber V rises, the valve closes to cut down the amountof solvent sprayed into the absorber, and as the level of the solution in the chamber V descends, the valve opens to increase the amount of solvent sprayed into the absorber.

Cooling water from a domestic source or water tower is conducted through the water pipe 24 to the condenser coil 25 within the condenser C and from th'ence by pipe 26 to a drain or is returned to the cooling tower. It is. preferable to provide a branch 21 from the waterpipe 24 to a coil 28 within the absorber A and from thence by pipe 29 to the outer larger coil 3|] of the residual heatcoil Y which in turn empties into a drain or is returned to the cooling tower. It is also preferable to provide a branch pipe 3| leading from the water pipe 24, to pass water through a coil 32 within the receiver R to the return or drain pipe 26 shown leading from the condenser.

It is preferable to provide a thermostatic valve 33 of commercial form in the connection between the coil 32 of the rectifier and the drain pipe 26 refrigerant.

The rectifier is so constructed 'as to allow the condensed solvent to drain into the v heater.

As shown in the wiring diagram, the wires L and L are connected to a source of commercial electricity and pass through thehand-operated switch S to the fluid fuel burner control box 34, shown for convenience mounted on the exterior of the boiler B. The control box 34 connects the commercial current to the operating mechanism of the fluid fuel burner, which is also provided with the customary electrical controls, which are not illustrated as they form no part of this invention. The commercial current entering the control box 34 is connected by wires 35 to the motor E for operating the pump 4 to return the condensate from the heater H to the boiler B when the oil burner mechanism is in operation. The motor M is connected in parallel to the leads L and L to the commercial source by wires 36 and 31 and the pump would normally operate to circulate the solution through the system of the refrigerating apparatus whenever the fluid fuel burner mechanism is in operation.

In order to maintain a temperature within a predetermined range in the cooling coil or evaporator9, a control is employed responsive to the pressure in the absorber to control the operation of the pump. Such a control 38 is a commercial product, such as manufactured by the Penn Electric Switch Company and disclosed in Patent Number 1,791,839, dated February 10, 1931. Such a control contains a switch connected in series in the wire 36 leading to the motor M. The switch 39 is provided with a pressure-actuated opening and closing device which is connected by the pipe 40 to the upper side of the absorber A and is so adjusted that a pressure of approximately 30 pounds per square inch within the absorber will close the switch, and upon a decrease in pressure to approximately 20 pounds per square inch, will open the switch and maintain it open until the a pressure again returns to approximately 30 pounds. The control 38 also contains a high pressure cut-out, which is connected by the pipe 4| to the interior of the condenser C, and is so adjusted that at a pressure of approximately 130 pounds per square inch within the condenser, the control will be operated to open the switch in the circuit to the motor M and maintain it open until the pressure returns to approximately 100 pounds per square inch. In the absorption refrigerating apparatus shown, the normal operating pressures of. the heater range from 80 to 110 pounds per square inch, and in the absorber from 25 to 35 pounds per square inch.

If the steam pressure becomes excessively low in the boiler for any reason, such as lack of heat, the temperature in the heater will not be sufiicient to boil off the normal amount ofrefrigerant, and refrigerant will be carried over with the solvent to the absorber A which will build up excessive pressure therein, and, if not controlled, will equalize the pressure in the heater and cause the apparatus to become inoperative. To prevent such a condition arising, an additional control is provided, which includes a commercial type of boiler or pressure control 42 containing a switch 43 connected in series with a wire 36 leading to the pump motor M. The commercial control of this character is responsive to steam pressure within the boiler so that when the pressure therein approaches a predetermined degree appreaching the danger mark, the control operates to open the circuit passing therethrough. In this application of this control, it is necessary to reverse the operation of the switch. The control illustrated is sold by The Mercoid Corporation and is constructed in accordance with Patent No. 1,734,016, dated October 29, 1929, in which the switch 43 is a mercury tube switch so that for the purpose of this invention the mercury tube switch is merely reversed, whereby as long as the pressure within the boiler remains above a predetermined degree, which in this case is approximately 5 pounds per square inch, the circuit through the control will be closed, and in the event that the pressure within the boiler descends below the predetermined degree, then the switch is opened and the operation of the pump motor M will cease.

In the diagrammatical view of the drawing, the cooling coil or evaporator 9 is shown installed within an air conditioning device mounted within the casing 44 which includes a motor Z operating a fan blower mounted within a casing 45 for circulating air over the cooling coil 9. As is customary, the expansion valve I adjacent the manifold of the high side of the cooling coil 9 is of that commercial type which is in effect a idle, and the temperature of the air, adapted to be drawn into the air conditioning device, is excessively high such as over 90 F., the thermostatically-controlled expansion valve 1 will allow some of the refrigerant to collect in the cooling coil 9 so that upon starting the operation of the apparatus, the fan blower passes a stream of air over the cooling coil 9, and the pressure in the cooling coil, and likewise in the absorber, as the low side manifold I0 is connected by pipe H to the interior of the absorber, will soon become excessive, as long as refrigerant continues to pass through the expansion valve into the coil, and soon the pressure within the absorber will equal that within the heater and cause the apparatus to become inoperative. In order to avoid such a condition arising, another control is provided which includes a pressure or boiler control 46 of commercial form connected to the interior of the absorber A connected in series with the wire 41 connected to the commercial mm L and to a solenoid-operated valve 48 of commercial form, which is also connected by the wire 49 to the lead L of the commercial source. This solenoidoperated valve 48 is connected in the pipe 6 between the condenser C and the expansion valve 1. This type of solenoid valve is opened-by the passage of an electric current through its windings, and will close when the current ceases. In a device of the character described, the pressure within the cooling coil 9 and the absorber A should not exceed 40 pounds per square inch. The pressure control 46is therefore adjusted so that its switch 50 will normally close the circuit through wires 47 and 49 maintaining the solenoid valve 48 open and when the absorber pressure As this valve is acomreaches 40 pounds per square inch, the control will open the switch 50, allow the solenoid valve 48 to close, out off the discharge of liquid refrigerant to the expansion valve and will remain desired and as an alternative form of control, the 1 solenoid valve 48 may be omittedand likewise the connections 5| and 52 to the motor Z and the motor Z connected by the wires 4''. and 49*, shown in dotted lines, which are extensions of the wires 41 and 49, and which in the other form were connected to solenoid valve 48. With this alternative form, when the device is started, the

fan blower motor Z will operate to pass air over the cooling coil 9 and if the pressure therein becomes excessive, the control 46 will open the circuit so that the passage of air over the coil 9 will cease until the pressure therein returns to normal.

The control of the motor M of the pump for circulating the solution does not necessarily depend upon a control 42 responsive to the steam pressurewithin the boiler B. The same result will be accomplished by a control of the same character which is operated by changes in the temperature of the water in the boiler, the temperature of the steam in the coils of the heater, or the temperature of the solution in the heater. Likewise, while the motor Z of the air conditioning device is shown as circulating air over the cooling coil 9,, it might be employed to circulate a stream of water over the cooling coil without departing from the scope of this invention.

What I claim is:

'1. In an absorption refrigerating apparatus including a heater, a condensenan evaporator and an absorber, an electrically-driven pump for circulating a solution of refrigerant and solvent. through the apparatus, and means in the pump circuit responsive to pressures in the absorber below the desired pressure'for efficient operation of the apparatus to open the pump circuit to discontinue the circulation of the solution and additional means responsive to pressure in the condenser above the desired pressure for efficient operation of the apparatus to open the pump circuit to discontinue the circulation of the solution, and wherein said means and additional 'means close the circuit to the pump upon reestablishment of the respective desired pressures.

2. In an absorption refrigerating apparatus includinga heater, a condenser, an evaporator and an absorber, an electrically-driven pump .for circulating a solution of refrigerant and solvent through the apparatus, and means in the pump circuit responsive to pressure in the condenser above the desired pressure for efficient operation of the apparatus to open the pump circuit to discontinue the circulation of the solution.

3. The structure of claim 2 wherein said means closes the pump circuit upon reestablishment of the desired pressure.

4. In an absorption refrigerating apparatus including a heater, a condenser, an evaporator, an absorber and an electrically-driven pump forcirculating a solution of refrigerant and solvent through the apparatus, a source of steam providing heat for the heater, and means in the pump circuit responsive to pressure of steam below the desired pressure for the efficient operation of the apparatus to open the pump circuit to discontinue the circulation of the solution.

5. The structure of claim 4 wherein said source of steam includes a steam boiler, and said means includes a control switch in the pump circuit responsive to pressure within the boiler.

6. The structure of claim 4 wherein said means closes the pump circuit upon establishment of the desired pressure.

7. The combination of an absorption refrigerating apparatus and an air conditioning device,

including the evaporator of the refrigerating apparatus and having a motor-driven means for circulating air over the evaporator, with a control in the motor circuit responsive to pressure in the absorber above the pressure desired for eflicient operation of the refrigerating apparatus to open the motor circuit. 1

8. The structure of claim '7 wherein said means, upon reestablishment of the desired pressure, closes the motor circuit.

9. In an electricallyeoperated and controlled air conditioning device, including an absorption refrigerating apparatus having a heater, a condenser, an evaporator, an expansion valve between the condenser and evaporator, and an absorber, a motor-driven pump for circulating a solution of refrigerant and solvent through the refrigerating apparatus,a steam boiler for furnishing heat to the heater and provided with an electrically-operated and controlled fluid fuelburning mechanism, motor-driven means for circulating the air to be conditioned over the evaporator of the refrigerating apparatus, a source of electricity, means to establish circuits from the source to the fuel-burning mechanism, to the pump motor for circulating the solution through the refrigerating apparatus and to the motor for a circulating air over the evaporator, respectively,

a control in the circuit to the pump motor responsive to pressures in the absorber below the desired pressure for eflicient operation of the apparatus to discontinue the pump circuit and responsive to pressure in the condenser above the desired pressure for efiicient operation of the apparatus to discontinue the pump circuit and, upon reestablishment of the respective desired pressures, to continue the said circuit, an additional control in the pump circuit responsive to pressure in the steam boiler below the desired pressure for efiicient operation of thev apparatus to open the pump circuit and, upon reestablishment of the desired pressure, to close the pump circuit, and an additional circuit to the source including a solenoid valve in the supply of refrigerant to the evaporator and a control responsive to pressure in the absorber above .the pressure desired in the evaporator for the efficient opera- 'burning mechanism, motor-driven means for circulating the air to be conditioned over the evaporator of the refrigerating apparatus, a source of electricity, means to establish circuits from the source to the fuel-burning mechanism, to the pump motor for circulating the solution through the refrigerating apparatus and to the motor for circulating air over the evaporator; respectively, a control in the circuit to the pump motor responsive to pressures in the absorber below the desired pressure for efiicient operation of the apparatus to discontinue the pump circuit and responsive to pressure in the condenser above the desired pressure for eflicient operation of the apparatus to discontinue the pump circuit and upon reestablishment of the respective desired pressures to continue the said circuit, anadditional control in the pump circuit responsive to pressure in the steam boiler below the desired pressure forefilcient operation of the apparatus to open the pump circuit and, upon reestablishment of the desired pressure, to close the pump circuit, and a control in the circuit to the motor for circulating air over the evaporator responsive to pressure in the absorber above the pressure desired in the evaporator for eflicient operation of the refrigerating apparatus to open the motor circuit to discontinue the circulation of air and, upon the reestablishment of the desired pressure, to close said circuit.

GLENN F. ZELLHOEFER. 

